Weapon swapping while on a Rhoa unmounts you and both both are stuck together...

when your riding the Rhoa then weapon swap, it:

1. Dismounts you
2. combines you and the Rhoa on top of each other as if your one walking
character
3. Makes you loose the 100% reduced movement speed penalty when using skills
since your now not mounted

Another bug is that you wont shoot shards from Ice-Tipped arrows while mounted on the Rhoa.

Thanks

I am having this issue as well.

Just wanted to add: this happens both when you swap your weapon with the dedicated key (x by default on keyboard and mouse), and also if you try to use skills assigned to different weapon sets - even if the second weapon set is a copy of the first weapon set.